


Taut Yet Malleable

by NyxAfterDark



Category: Rick and Morty
Genre: Anal Fingering, Anal Sex, C137cest, First Time, Incest, M/M, Semi-Public Sex, i saved this on my pc as SIN
Language: English
Status: Completed
Published: 2017-10-19
Updated: 2017-10-19
Packaged: 2019-01-19 13:34:23
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 2,401
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/12411273
Author URL: https://archiveofourown.org/users/NyxAfterDark/pseuds/NyxAfterDark
Summary: Morty agrees to smuggle the mega seeds in his butt. There's just one problem: they won't fit, and the only person who can help is Grandpa Rick. Actually, there's another problem: it turns out that Morty really loves having Rick's fingers up his ass, and that Rick really loves putting them there.





	Taut Yet Malleable

**Author's Note:**

> i'm not gonna waste my time with a disclaimer. this fic is what it is. read it if you want to or fuck off. i'm not your mom, and i'm not gonna coddle you.

For the umpteenth time in the last 25 minutes, Rick glanced at his watch and wondered what was taking Morty so long. It had been nearly three-quarters of an hour since Morty had slipped into the bathroom with the mega seeds, and he still hadn’t reappeared.

With an exasperated huff, Rick sidled into the bathroom.

“M-Morty?” he called out, “What’s taking s-so long?”

He waited impatiently for Morty’s stammering response, listening intently to ascertain which stall he had gone into.

After a moment, he heard a sniffle and then Morty spoke from the stall at the end. “I-I-I-I can’t do it R-Rick.” His voice was wavering.

Rolling his eyes, Rick sauntered over and tapped on the door. “Lemme in,” he said quietly.

There was a silence, and then the latch clicked and Morty was revealed.

He was dishevelled, sitting on the lid of the toilet, clearly distraught. In his hand was a mega seed, the other resting on his discarded pants. His underwear had been hastily yanked up, inside out, and his shirt was smeared with tears or lube or both.

“I-it’s too big,” he stammered. “I c-can’t – it won’t – I’m not…” he trailed off, his red-rimmed and shame-filled eyes meeting Rick’s. He seemed to hesitate on his next sentence, the words caught in his throat. Then, almost inaudibly, with an edge that Rick might have mistaken for desperation, he murmured,

“Help me.”

There was not much in the universe that surprised Rick. But Morty’s shaky plead took him aback. But, as ashamed as he looked, Morty’s gaze remained locked steadfast with Rick’s, and the scientist knew the request was serious.

And for an instant, he considered it. Only for an instant, before firmly denying his brain the opportunity to think about the consequences. To think about Morty’s body writhing underneath him – _No_.

“P-please.” Having seen the firm denial on Rick’s face, Morty uttered another trembling plead.

Later, Rick would blame the booze. He’d blame the situation, or his dire need for these seeds, or Morty’s quivering lower lip; anything, _anything_ , that could possibly explain why, in that moment, his resolve wavered and then crumbled.  

With the dexterity of someone much younger, he pulled Morty’s compliant body forward, swivelled, and sat on the toilet lid. In a swift movement, he freed Morty of his underwear and pulled him forward. Morty’s body obeyed, and before either of them really comprehended the situation, Morty was settled on Rick’s lap, one leg on either side of the older man, dangling just above the ground.

“O-oh…” Morty breathed, his eyes widening slightly.

Rick swallowed thickly, trying to detach himself from the situation. “Just… let’s just get this over with.”

Without an ounce of feeling, Rick slid his hands to his grandson’s ass and gently pulled his cheeks apart, the tips of his fingers brushing lightly against the boy’s over-sensitive hole.

Morty shuddered, almost imperceptibly, and his hands lifted from his lap to grip tightly at the lapel of Rick’s coat. His fingers were shaking, just a little, but he said nothing in protest.

Taking his silence as encouragement to continue, Rick ran his fingertip over Morty’s hole once again, firmly, and insistently. He wanted to rush, to get this over with so he didn’t have to think too much about it – but something in Morty’s shaky breaths told him the boy needed more time to process what was about to happen.

While Morty attempted to even out his breathing, Rick took a packet of lube from his jacket and squeezed some out onto his fingers. He hesitated then, trying his best to remain clinical and detached, and not entirely succeeding. But time was ticking, and these seeds wouldn’t stay useful forever. So, with one last deep breath, he gripped Morty’s ass in one hand and, steadily, began to push a finger into his grandson.

He felt Morty tensing, his grandson’s clammy forehead pressing against his clavicle, where he could feel shaky breaths.

“You-you gotta relax, M-Morty,” he said quietly, continuing to press insistently at Morty’s tight asshole. “I’m not g-gonna hurt you. Just bre-eathe.”

He waited for a moment, until he felt Morty relax slightly against him. He calmed himself for a second, and in one swift motion, buried the first finger completely inside Morty. Unexpectant, his grandson jerked, gasping. And then, shuddering, he slumped heavily against Rick, breathing unevenly.

Not allowing himself to hesitate, Rick moved his finger in and out slowly, giving Morty time to adjust before he added a second finger. When Morty’s erratic breathing seemed to be steadying, Rick pulled out and began the process over with a second finger. There was less resistance this time, and Rick buried two fingers easily. With two fingers inside his grandson, Rick almost swore he felt Morty move against his hand, but quickly dismissed the possibility.

When he added a third finger, and began pumping in and out steadily, Morty’s reaction was harder to ignore. With every agonizingly slow push, Morty was writhing imperceptibly, his ass pressing down on Rick’s hand subtly. His fingers, holding onto Rick’s lapel, were turning white with the tightness of his grip. Rick swallowed hard, forcing his breathing to steady as he willed his body to calm down.

But when he scissored his fingers inside Morty, intending to stretch him enough to accommodate the mega seeds, Morty did something that made him forget entirely about the seeds. Made him forget about everything about the body pressing heavily against his.

Morty _moaned_.

His grandson immediately began spluttering, uncomfortably attempting to obscure the unmistakable noise.

“I- uh, aw jeez I, um,” he stammered, his face turning red.

“Stop,” Rick said, an edge to his voice that even he could hear. Morty stilled, immediately, uncertain.

But Morty’s moan had done something to Rick, had done something to his steadfast resolve that couldn’t be undone. Heat spread through his body, licking down his spine. He met Morty’s ashamed gaze and with a deliberate, measured movement, curled his fingers in Morty’s ass, pressing gently against his grandson’s prostate.

The effect was immediate. Morty’s jaw slackened, his eyes glazing over for a moment. But best of all, he couldn’t seem to stop himself from eliciting another moan. It was a quiet mewl, and it was _delicious_. Rick’s lip lifted into a smirk, and he repeated the movement with more insistence.

This time Morty’s mewl was a fully formed moan, and he jerked. He seemed to realise, as his body rubbed against Rick’s, that he was not the only one who was hard. Under his eyelashes, Rick saw his gaze slide to where their crotches met. Morty’s dick was already exposed, hard and leaking – but undeniable under Rick’s tight corduroys was his own straining erection.

“O-Oh,” Morty breathed, his gaze meeting Rick’s, just as Rick brushed against his prostate once more. “O- _Oh_!” he repeated, his eyes rolling back into his head for a second at the sensation.

The booze and the arousal clouded Rick’s judgement. Using the fingers buried in Morty as well as his second hand cupping a handful of Morty’s ass, he pulled his grandson closer, and up slightly. In the space created, he had just enough room to reach under and unzip his pants. His dick was already straining at the fabric, and popped free easily. As it shook slightly from the movement, Morty felt it touch his ass, and shuddered.

“R-Rick we –”

“Shut up,” Rick said forcefully, emphasising his point by curling his buried fingers pointedly. Morty’s protests died in his throat and were replaced by a breathy groan.

“O-Oh God R-Rick,” he stammered, burying his face in Rick’s chest. “I want – I want –“

“Shh,” Rick murmured. “I know.”

Momentarily removing his fingers from Morty’s ass, Rick pushed himself backwards, until his back hit the cistern. He leaned back slightly and Morty, pressed against him, leaned forward with him but Rick took him by the shoulders and pushed him upright, so Morty was more or less sitting atop him. Morty seemed self-conscious in this new position, unable to hide away in Rick’s chest. Bashful, he made to cover his weeping erection, but Rick caught his hands in his.

“No.”

Swallowing visibly, Morty instead rested his hands against his grandfather’s stomach, as Rick fumbled with his erection behind Morty’s ass. Unprompted, Morty raised himself slightly, and Rick smirked, almost proudly, his fingers gripping Morty’s hip.

Morty jerked slightly at the first nudge against his asshole, something in him protesting despite his clear arousal. But Rick’s fingers at his hip held him still, and he didn’t move again. The warm, hard head of Rick’s dick pressed against Morty’s ass a second time, and this time the boy responded to the push with one of his own. He lowered himself just enough for Rick’s dick to catch, but went no further.

He met Rick’s lust-filled gaze and trembled slightly. “I’m – I’m scared Rick,” he said quietly. His fingers gripped at Rick’s shirt, bunching the material.

Rick shushed him quietly, and with both hands on his grandson’s hips now, he began to pull the boy’s hip downwards. Breathing heavily, Morty forced himself to relax, allowed his body to open and take his grandfather’s cock without resistance.

Rick didn’t allow himself to stop until he felt the head of his dick slip inside. He waited then, allowed Morty to adjust to the strange sensation. But Morty, God bless him, immediately began to writhe.

“R-Rick,” he whisper-moaned. “I – more. P-please.”

“Ungh,” Rick replied headily, his dick twitching at the sight of his grandson squirming and pleading to be fucked.

Perhaps not as slowly as he should have, he dragged Morty’s hip downwards, lifting his own simultaneously. Morty’s erratic breathing turned into a pant, his eyes half-closing with pleasure. His dick, already red, twitched sharply and a drop of pre-cum leaked from the tip. Taking that as encouragement, Rick smirked and dragged Morty all the way down, burying his cock completely in his grandson’s ass.

“Ugh, fuck M-Morty,” he couldn’t stop himself from saying, as Morty’s tight ass clenched around him. “F-fuck you’re so ti-ight.”

Morty flushed, his fingers digging into Rick’s hips slightly. In response, he seemed to push himself even lower, his hips twisting slightly. His inexperienced attempt to fuck himself on Rick’s dick nearly made the older man cum then and there, but he held himself back. Instead, he gently guided Morty’s hips, moving him up and forward, before plunging him back down, meeting his downward thrust with an upward thrust of his own. Morty gave a half yell, half moan, and Rick chuckled.

“G-good thing they don’t have sex the s-same way we d-do,” he said slyly, meaning the rest of the aliens outside. “Or you-you’d have given us a-away.”

His flush deepening, Morty bit his lip. The sight made Rick groan, and giving up on restraint, he began fucking Morty in earnest. He guided Morty’s hips for a few more thrusts before allowing Morty to take up his own rhythm. He matched Morty’s bouncing movements, gripping the boy’s ass with bruising fingers.

With every thrust Morty moaned and, as Rick quickened the pace, he began to unravel, falling out of rhythm. His fingers were digging painfully into Rick’s hipbones, and he seemed to be trying to say something over the gasping moans. Rick slowed his thrusts to give him a chance to speak.

“I’m gonna – gonna – oh God please,” Morty gasped out, his eyes fluttering shut.

Rick grinned and returned to thrusting afresh. He could feel himself getting close, Morty’s tight ass clenching around his length. He knew Morty was close too, could see his dick weeping non-stop as he focused on riding Rick’s cock.

Almost devilishly, and without warning, Rick wrapped his fingers around Morty’s seeping dick and gave him a rough tug. Morty gave a choked cry, his eyes flying open, and came over Rick’s hand and shirt, jerking on Rick’s cock.

Sitting up and holding Morty firmly, Rick fucked up into his grandson as he came, relentlessly fucking him through his orgasm until he felt his own crashing over him. He came inside Morty with a grunt, relishing the way Morty’s ass continued to twitch around him even after he had come. He thrust a few more times, enjoying how Morty’s softening dick began to jerk back to life, before pulling his own softening cock from his grandson’s ass.

He grabbed Morty by the shoulders and manoeuvred him back down on the toilet seat. Blearily, Morty gazed up at him. After tucking himself back into his pants, Rick leaned around Morty and picked up the discarded mega seed, handing it to the confused boy.

“It should fit now,” he said, almost callously, and Morty blinked. “We gotta get through security, so make it quick.”

Without another word, Rick unlocked the cubicle and slipped out. No one seemed to notice him, or care, and he went back to wait in the security line.

A few moments later, Morty joined him, rubbing his backside. Rick glanced at him, noticed the way the boy’s cheeks flushed.

“Did you get those seeds all the way up your butt?” he asked as nonchalantly as he could.

Out of the corner of his eye, Rick saw Morty’s face harden. “Yeah. Let’s just get this over with.”

~*~*~

Rick was in his garage a few days later, once Morty had recovered from the seeds effect on his brain function, when his grandson opened the door.

“Rick?” Morty asked, a strange edge to his voice.

Rick took a second to get the image of Morty writhing on his cock out of his mind, before throwing a casual “What?” over his shoulder.

Morty closed the garage door behind him, clearing his throat almost awkwardly.

“What do you want?” Rick asked brusquely, not quite meeting his grandson’s eye. If he wasn’t mistaken, Morty wasn’t quite meeting his either.

Morty cleared his throat again, shuffling his feet awkwardly. “About the seeds…” he began, trailing off as Rick looked sharply at him. Then he seemed to find his courage, clearing his throat again and lifting his chin. He met Rick’s gaze without flinching.

“I was wondering if we could go and get some more,” he said, as nonchalantly as Rick had been.

“Y-you want more?” Rick asked, knowing full well he wasn’t asking about the seeds.

Morty almost-smiled. “I want lots more,” he replied.

And God fucking help him, Rick wanted more too.

**Author's Note:**

> i didn't proofread this before posting so if i got the names muddled up at any point, that's my b. hope you enjoyed, please leave kudos or a comment ♥


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